1. Field of the Invention
The invention generally relates to a dual-gate or split-gate FinFET structure and method that can be built on a conventional SOI wafer where, in a first embodiment, the back gate is built at the same level as the front gate, and the gate wiring uses sidewall-image transfer (SIT) shapes, and where, in a second embodiment, the back gate is buried and is fabricated by replacing the buried oxide layer with an oxide-conductor-oxide layer.
2. Description of the Related Art
A fin-type field effect transistor (FinFET) is a type of transistor that has a fin transistor channel covered by a gate conductor. The gate conductor covers the channel portion of the fin and source and drain portions of the fin extend beyond the coverage of the gate conductor. FinFETs are discussed at length in U.S. Pat. No. 6,413,802 to Hu et al. (hereinafter “Hu”), which is incorporated herein by reference.
Dual-gate transistors have electrodes on either side of a MOS channel. For thin body transistors, especially FinFET transistors, having a back gate is a method for achieving threshold voltage control when the channel is essentially fully-depleted. This disclosure introduces a split-gate FinFET structure and method that can be built on a conventional SOI wafer.